1. Field of the Invention
The present invention relates to an electronic device, a remote control device capable of remotely controlling an electronic device, and a remote control system including an electronic device and a remote control device.
2. Description of the Related Art
In a remote control system, in response to the manipulation of user-operated keys or buttons of a remote control device, a control signal (e.g., infrared rays, radio waves, etc.) is transmitted from the remote control device to an electronic device (e.g., a television) to thereby control an operation of the electronic device.
Generally, it takes time to fully activate an electronic device from a turned-off state. For example, in an older television, time is required to sufficiently heat a cathode-ray tube. Further, in more modern televisions having a liquid crystal panel or plasma panel, time is expended to initialize a signal processing circuit.
In an effort to reduce activation time, a technique has been suggested in which a turn-on process is automatically triggered upon detecting that a remote control unit has been tilted (picked up), i.e., before the user has actually pushed any buttons. See, for example, Japanese Patent Application Laid-Open No. 2007-088753. However, this technique results in relatively poor efficiency since circuits having a short activation time are activated simultaneously with the circuits having a long activation time. Also, electric power is needlessly consumed if a long period of time occurs between activation and actually operation of the remote control unit.
Moreover, when a radio wave is used as transmitting medium of the remote control device, the standby power consumption of a wireless transmitting/receiving circuit for transmitting/receiving the radio wave is problematic. That is, particularly when the wireless transmitting/receiving circuit is set to a continuous reception state during a standby mode, the standby power consumption increases. An intermittent operating mode may be adopted to decrease standby power, but this results in an increase in average delay time to fully turn-on the electronic device.